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In physics, the Lyman-alpha line is a spectral line of hydrogen, or more generally of one-electron ions, in the Lyman series, emitted when the electron falls from the n = 2 orbital to the n = 1 orbital, where n is the principal quantum number. In hydrogen, its wavelength of 121.6 nanometres, corresponding to a frequency of 2.47 × 1015 hertz, places the Lyman-alpha line in the far ultraviolet part of the electromagnetic spectrum.
Additional recommended knowledge
A K-alpha or Kα line analogous to the Lyman-alpha line for hydrogen, occur in the high-energy induced emission spectra of all chemical elements, since it results from the same electron transition as in hydrogen. The equation for prediction of the frequency of this line (usually in the X-ray range for heavier elements), uses the same base-frequency as Lyman-alpha, but modified by a (Z-1)² factor to account for differing atomic numbers (Z) between elements, and is expressed as Moseley's law. The Lyman-alpha line and the rest of the hydrogen Lyman spectral series are most simply described by the empiric Rydberg equation and semi-classic Bohr model of the atom.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Lyman-alpha_line". A list of authors is available in Wikipedia.|